MACROINVERTEBRATE DIVERSITY AND WATER QUALITY PATTERNS OF A MUNICIPAL STREAM IN DOKO DISTRICT,NIGER STATE,NIGERIA

Abstract

The macroinvertebrate community of Emikpata stream, Doko district, Niger State, Nigeria were studied for a period of eight months using the modified kick sampling techniques. Four well marked stations were selected along the course of the stream designated as station 1, 2,3,4.Physicochemical parameters examined and readings were: Water temperature (23.0-27.0℃c),Depth (20.96-24.10cm), Flow velocity (0.29-0.30m/s), Dissolved oxygen (5.97-6.35mg/l),Biochemical oxygen demand (3.25-3.87mg/l), pH (6.0-6.32, Conductivity (49.1-110.0μS/cm),Total hardness (12.3-18.0mg/l), Total alkalinity (13.0-20.5mg/l), Chlorine (10.71-32.79mg/l),Nitrate (1.83-3.69mg/l), Phosphate (0.60-1.12mg/L), Sodium (7.24-9.02mg/l), Potassium (1.74-1.92mg/l). A total of 625 individuals from 28 species and 19 families of invertebrate were recorded. Significantly higher (P<0.005) macroinvertebrate abundance was recorded during the dry season as compares to the wet season. The Canonical Correspondence Analysis (CCA)result showed strong relationship between species abundance and measured environmental variables. Higher population of pollution tolerant macroinvertebrates groups and the poor water quality observed during the sampling period were indications of pollution stress occasioned by anthropogenic activities, decomposing domestic wastes and inorganic fertilizer washed into the stream from various nearby farms.